Sermin Öztekin

Preemptive diclofenac reduces morphine use after remifentanil-based anaesthesia for tonsillectomy

Summary Background: We investigated the effect of preincisional rectal diclofenac on pain scores and postoperative morphine requirements of children undergoing tonsillectomy after remifentanil‐propofol anaesthesia in a randomized clinical trial.

The effects of gender and menopause on serum lidocaine levels in smokers

SummaryIt has been established that human cytochrome P450 (CYP) enzymatic activity is affected by gender, or by hormonal factors such as the menopause in women. Gender differences have a more pronounced effect on cytochrome (CYP) 3A4 isoenzyme activity, whereas cytochrome (CYP) 1A2 isoenzyme activity is mainly induced by chronic smoking. Lidocaine is frequently used in the treatment of hemodynamic changes following laryngoscopy and tracheal intubation during general anesthesia, and is metabolized by CYP3A4 and CYP1A2 isoenzymes in the liver.The aim of this study was investigate the effects of gender and menopause on serum lidocaine levels in smokers under general anesthesia. Six men, six premenopausal women and six postmenopausal women were enrolled in the study and received i.v. lidocaine (1 mg/kg) 1 minute before they underwent general anesthesia. Serum lidocaine concentrations were measured using the EMIT® method at 1, 5, 10, 20, 40 and 60 minutes post-administration. Statistical analyses were performed using the Mann-WhitneyU-test.No statistically significant differences were found regarding the area under curve (AUC(0−60) μg/mL/min), elimination half-life (t1/2 [min]) of lidocaine and in the measured levels of serum lidocaine at any time point between the study groups (p>0.05). These results suggest that gender and menopause may have no significant effect on serum lidocaine levels in smokers.

Low doses of rocuronium during remifentanil-propofol-based anesthesia in children: comparison of intubating conditions.

Background : In this prospective double‐blind study, intubation conditions were compared at 90 s following two different low doses of rocuronium during remifentanil and propofol anesthesia in children undergoing ambulatory procedures.

Comparison of the Antiemetic Efficacy of Tropisetron and Droperidol with Patient-Given Tramadol

We compared the antiemetic efficacy of tropisetron versus droperidol in women given tramadol after total hysterectomy. Forty patients were randomly allocated to group 1 (n = 20, tropisetron 0.05 mg/kg intravenously) or group 2 (n = 20, droperidol 15 μg/kg intravenously). Tramadol infusion (intravenously), for post-operative analgesia, was started at fascia closure. Incidences of post-operative nausea and vomiting, pain intensity, tramadol use, and the need for a rescue antiemetic (metoclopramide 10 mg) were recorded 0 h, 2 h, 6 h, 12 h, 24 h and 48 h post-operatively. Vomiting and nausea incidences were reported fewer in group 1 than in group 2, but statistical significance was only reached for vomiting incidence 6 h post-operation. Tropisetron seems to have better antiemetic properties than droperidol in patients receiving tramadol, because of the length of its duration of action. Further studies, investigating alternative ways of managing postoperative nausea and vomiting, and the use of tramadol for post-operative analgesia, are needed.

Comparison of the Haemodynamic Effects of Interscalene Block Combined with General Anaesthesia and Interscalene Block Alone for Shoulder Surgery

Interscalene brachial plexus block (ISB) anaesthesia is widely used with or without general anaesthesia in patients undergoing shoulder surgery, which is generally done with the patient in a sitting position. This position affects haemodynamics, and supplementing ISB with general anaesthesia can exaggerate these haemodynamic changes. This study compared ISB combined with general anaesthesia, with ISB alone, in 29 patients undergoing elective shoulder surgery. Heart rate and oxygen saturation remained stable throughout the study in both groups. Mean arterial pressure was significantly decreased when the patient moved into the sitting position in those given combined anaesthesia, whereas in those given ISB alone mean arterial pressure did not change significantly. Neither pain scores nor patient satisfaction scores differed significantly between the two groups. All of the patients were either satisfied or entirely satisfied with their anaesthesia/analgesia. There were no significant differences in side-effects and no severe complications in either group. We advocate using ISB alone for patients undergoing shoulder surgery, but further larger studies are needed to confirm the present results.

The effects of propofol on normal and hypercholesterolemic isolated rabbit heart

The aim of the present study was to compare the effects of propofol on cardiac contractile force in normal and hypercholesterolemic isolated rabbit hearts. While one group was fed with standard chow pellets (150 g/day), the other group received cholesterol (1% w/w) in addition to the same amount of rabbit chow pellets during 1 month. Hearts from standard-fed rabbits were given intralipid solvent or 25, 50 and 100 microM propofol by infusion. Hypercholesterolemic rabbit hearts were administered 25, 50 and 100 microM propofol by infusion. All concentrations of propofol did not result in any significant change of the heart rates (HR) in two groups. Propofol (25, 50 and 100 microM) infusion induced a concentration- and time-dependent inhibition in left ventricular pressure (LVP) in standard chow diet group (P<.05,.05 and.05, respectively). In hypercholesterolemic rabbit hearts, 25 and 50 microM propofol infusion developed a significant inhibition in LVP when compared with the standard chow diet group (P<.05 and.05, respectively). Propofol (100 microM) infusion developed a significant increase in LVP after 20 min in hypercholesterolemic rabbit hearts when compared with normal rabbit hearts (P<.05). Supratherapeutic concentration of propofol might have cardioprotective effect on hypercholesterolemic rabbit hearts.

The Effect of Midazolam Pre-Medication on Rocuronium-Induced Neuromuscular Blockade

We investigated the effect of midazolam pre-medication on rocuronium-induced neuromuscular blockade during sevoflurane anaesthesia. Twenty-two patients scheduled for elective surgery were randomly divided to receive either no pre-medication (control group) or pre-medication with 0.1 mg/kg midazolam intramuscularly (midazolam group). Anaesthesia was induced with fentanyl and propofol, and maintained with sevoflurane and nitrous oxide in oxygen. Neuromuscular responses were monitored using acceleromyography. The onset and clinical duration of action, time to recovery of first twitch of train-of-four (TOF) response to 75% of control, recovery index and time for TOF recovery to 25% and 50% were recorded. Patient-related data were similar in both groups. The parameters recorded were not significantly different between the groups. Midazolam pre-medication does not influence the time-course of action of rocuronium during sevoflurane anaesthesia.

Endotracheal intubation without neuromuscular blocking agents: is it a good and safe option?

Dear Editor, We read with great interest the article, “Use of Remifentanil and Alfentanil in Endotracheal Intubation: A Comparative Study,” by Imani et al. (1). The authors demonstrated that remifentanil in combination with propofol provides excellent conditions for endotracheal intubation in young, healthy patients to avoid the use of muscle relaxants. However, there are some points about the article’s focus and results that we would like to discuss in this commentary. Propofol in combination with an opioid has been used by many investigators to facilitate neuromuscular blocking agent-free intubation. In most of these studies, at doses of remifentanil 2 µg/kg and above, blood pressure and heart rate were significantly reduced compared with baseline levels; this anesthetic technique with high doses of remifentanil caused severe cardiac depression in adults (2-4). In this study, the authors used a very high dose of remifentanil (5µg/kg) but did not give any data about the hemodynamic variables. In the literature, there are still patients with unacceptable responses to intubation even after high doses of remifentanil. Klemola et al. showed that intubation was impossible in 25% and 5% of adult patients who received remifentanil 3 and 4 µg/kg, respectively (5). Although Imani et al. claimed that intubating conditions were quite suitable in most of the patients in this article, we noticed that there were two patients in the alfentanil group with a vocal cords’ patency score of 4 and 14 patients with a vocal cords’ patency score of 3 (in Table 3). We do not see how these patients had clinically acceptable intubating conditions, and we wonder if there were any patients who could not be intubated? Also, the authors did not provide any data about the adverse events related with laryngeal morbidity. Mencke et al. reported that the quality of tracheal intubation contributed to laryngeal morbidity, and excellent conditions were less frequently associated with postoperative hoarseness and vocal cord sequelae. In addition, they concluded that vocal cord sequelae occurred more frequently in patients who were intubated without muscle relaxants and that the addition of nondepolarizing muscle relaxants to a propofol–fentanyl induction regimen improved the quality of tracheal intubation and decreased postoperative hoarseness (6). In another study, Holzki et al. demonstrated that stridor was not a main outcome measure for assessing airway injury after extubation (7). Stridor might develop weeks or months after airway injury, and only endoscopy can clearly detect all airway injuries. Further, in a Danish report, Lundstrom et al. concluded that avoiding neuromuscular blocking agents might increase the risk of difficult tracheal intubation, which is often related with minor airway injuries (8). Therefore, anesthesiologists should aim for excellent intubating conditions in all cases to avoid causing laryngeal morbidity. Finally, the article concentrates on the technique to intubate the trachea without muscle relaxation. As we mentioned before, the literature describes some techniques to intubate the trachea without the use of neuromuscular blocking agents under general anesthesia. However; the question remains as to whether it is a safe and good option. Combes et al. compared two induction regimens using or not using a muscle relaxant and concluded that the use of a muscle relaxant for tracheal intubation diminishes the incidence of adverse postoperative upper airway symptoms, results in better tracheal intubation conditions, and reduces the rate of adverse hemodynamic events (9). In short procedures in which endotracheal intubation is mandatory but muscle relaxation for surgery is not required, such as certain Ear Nose Throat (ENT) and neurosurgical procedures, reduced doses of neuromuscular blocking agents can be used to facilitate the endotracheal intubation. Oztekin et al. suggested the use of a reduced dose of rocuronium (0.3 mg/kg) with propofol (2.5 mg/kg) and remifentanil infusion (0.5µg/kg/min) to obtain satisfactory intubating conditions without any cardiovascular instability in pediatric day-case surgery (10). Furthermore, sugammadex, a new agent that allows prompt reversal of both rocuronium and vecuronium, should be kept in my mind for very short procedures as well as certain neuromuscular disorders in which reduced doses of rocuronium can be used to facilitate endotracheal intubation. Succinylcholine is also an alternative depolarizing neuromuscular blocking agent for short procedures and rapid sequence induction (crush intubation). However, succinylcholine is contraindicated in certain conditions (e.g., choline-esterase enzyme deficiency, recent spinal cord injury, burns, hyperkalemia, susceptibility to malignant hyperthermia). In rapid sequence induction, high doses of rocuronium (1 to 1.2 mg/kg) can be used as an alternative to succinylcholine, but if the procedure is very short, sugammadex can help to reverse the neuromuscular blockage. Nevertheless, in practice, there may be some cases in which both depolarizing and nondepolarizing muscle relaxants are contraindicated and sugammadex is not available; in such cases avoidance of neuromuscular blocking agents for intubation can be a valid or even unavoidable technique in the anesthetist’s armamentarium. Therefore, the authors’ attempt in this research area is commendable.

Effects of different doses of remifentanil on hemodynamic response to anesthesia induction in healthy elderly patients

Abstract Objective: We compared the effects of three different doses of remifentanil infusion, which were performed for the induction of anesthesia in elder patients, on cardiovascular response. Research design and methods: The present study was designed as a randomized, prospective and double-blind study. A total of 90 ASA I–II patients over the age of 65 years were enrolled. The patients were randomly (by lot) assigned to receive one of the three doses of remifentanil infusion (0.1, 0.2 or 0.3 μg/kg/min) for two minutes. Subsequently, 0.5 mg/kg propofol was administered via IV route and 0.5 mg/kg rocuronium was administered via IV route at the time eyelash reflex disappeared. Intubation was performed after 2 minutes. Patients who had an allergy against opioids, were chronic substance users, were obese, expected to have difficult airway, had hypertension, or were receiving any drug influencing the cardiovascular system were excluded. Main outcome measures: In this study after recording baseline values of heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP), these values were recorded at the 1st, 2nd, 3rd, 4th and 5th minutes of induction. Results: A significant increase was observed in heart rate at the 1st and 2nd minutes of induction versus baseline in the Remi 0.1 group and at the 2nd minute of induction versus baseline in the Remi 0.2 group, with no additional significant change in heart rate. A significant decrease was determined in the systolic, diastolic and mean arterial pressures in all groups from the 1st minute of induction of anesthesia to the pre-intubation period compared to baseline (p < .05). Conclusions: It was determined that each dose of remifentanil used was quite high for patients of this age-group. ClinicalTrials.gov trial number: NCT02763098.

The Effect of Lidocaine on Injection Pain of Different Propofol Concentrations in Patients Receiving Remifentanil

ABS TRACT Ob jec ti ve: The ef fec ti vity of re mi fen ta nil and li do ca i ne com bi na ti on on the in jec ti on pa in with 1% pro po fol was re por ted pre vi o usly. Ho we ver, this fin ding has not be en in ves ti ga ted with dif fe rent pro po fol con cen tra ti ons. In this pros pec ti ve, ran do mi zed, do ub le-blind tri al, we ai med to com pa re the ef fect of li do ca i ne on the in jec ti on pa in of 1% or 2% pro po fol in pa ti ents re ce i ving re mi fen ta nil. Ma te ri al and Met hods: One hun dred pa ti ents un der go ing ear-no sethro at sur gery we re ran domly as sig ned into fo ur gro ups (n= 25 each). Fol lo wing 0.5 μg/kg/min re mi fen ta nil, pa ti ents in Gro up 1 and Gro up 2 re ce i ved 1 mg.kg-1 1% or 2% pro po fol the mi xed with 2 mL of sa li ne, res pec ti vely. Pa ti ents in Gro up 3 and Gro up 4 re ce i ved 1 mg.kg-1 1% or 2% pro po fol mi xed with 2 mL of 2% li do ca i ne af ter 0.5 μg kg-1 min-1 re mi fen ta nil. Pa in du ring the injec ti on of pro po fol was as ses sed on a fo ur-po int sca le (0= no ne, 1= mild, 2= mo de ra te, 3= se ve re) Re sults: The in ci den ce of no ne-mild pa in on in jec ti on of 1% pro po fol was sig ni fi cantly lo wer in Gro up 1 (56%) com pa red to Gro up 3 (100%) (p= 0.00017). This fin ding was al so seen bet we en Gro up 2 (36%) and Gro up 4 (72%) (p= 0.010). Ho we ver, the num ber of pa ti ents suf fe ring from the in jec ti on pa in was sig ni fi cantly gre a ter in Gro up 4 com pa red to Gro up 3 (p= 0.004). Conc lu si on: Li do ca i ne 2% 2 mL mi xed with pro po fol comp le tely abo lis hed mo de ra te-se ve re pa in in du ced by 1% pro po fol in pa ti ents who we re gi ven 0.5 μg/kg/min re mi fen ta nil. Ho we ver, so me pa ti ents still suf fe red from in jec ti on pa in ca u sed by 2% pro po fol in spi te of the com bi ned ef fect of li do ca i ne and re mi fen ta nil.